Lubricating refrigeration systems



Dec. 6,. 19%6 E. D. MUSIC EEWAZG LUBRICATING REFRIGERATION SYSTEMS FiledFeb. 17, 1966 2 Sheets-Sheet l I? LEE-5T2 mviimog. EAQL 0, Mus/ 0 Dec.6, 1966 E. D. MUSIC 3389 426 LUBRICATING REFRIGERATION SYSTEMS FiledFeb. 17, 1966 2 Sheets-Sheet B INVENTOJ 5/4131 0o Mus/c W Q WQZW UnitedStates Patent 3,289,426 LUBRICATING REFRIGERATION SYSTEMS Earl DeanMusic, 416 S. Main, Elk City, ()kla. Filed Feb. 17, 1966, Ser. No.548,113 12 Claims. (Cl. 6277) This is a continuation-in-part ofapplicants co-pending application of the same title, Serial No. 430,984,filed February 8, 1965.

This invention relates to an improved method and apparatus forlubricating a refrigeration system.

As is well known in the art, most refrigeration systems utilized inhomes and commercial buildings utilize a compressor, condenser,evaporator and an expansion device between the condenser and theevaporator. As is also well known, such refrigeration systemsperiodically require the addition of oil for lubrication of thecompressor and the motor driving the compressor.

In the past it has been the practice to pump the refrigeration systemdown in order to lubricate the compressor and motor, which actionrequires a substantial period of time. Also, pumping the system down andsucking lubricating oil into the system almost invariably leaves aslight amount of air and moisture in the refrigeration system. Further,servicemen frequently get dirt in the compressor during the lubricationof the compressor as it has been practiced in the past.

The present invention contemplates a novel method of lubricating arefrigeration system having a compressor, comprising the steps ofpartially filling a container assembly with lubricant for therefrigeration system; forcing refrigerant of the type used in therefrigeration system under pressure through the container assembly abovethe lubricant therein to remove substantially all of the air from thecontainer assembly. The container assembly is then inverted and thelowermost end of the inverted container assembly is connected to thesuction side of the compressor. Refrigerant is then applied to thecontainer assembly under a pressure greater than the suction pressure ofthe compressor to fill the space above the lubricant in the invertedcontainer assembly and force lubricant from the container into thecompressor suction until the desired amount of lubricant has beensupplied to the refrigeration system.

The present invention also contemplates a novel system for lubricating arefrigeration system having a compressor, While the refrigeration systemis in operation, comprising an invertible container assembly having anupper end and a lower end and having inlet and outlet connectors on theupper end thereof. A supply of lubricant is contained in the containerassembly and partially fills the container assembly, and a hose isconnected to the outlet of the container assembly, and to the suctionside of the compressor. Means are provided, such as in the form of abottle of refrigerant and a control valve, for forcing refrigerant underpressure through the upper portion of the container assembly and thehose when the container assembly is in an upright position to remove airfrom the upper portion of the container assembly and the hose, and forfilling the space above the lubricant for forcing the lubricant from thecontainer and through the hose into the suction of the compressor whenthe container is in an inverted position.

An object of the invention is to decrease the cost of lubricating arefrigeration system which has been in operation.

Another object of the invention is to minimize the time required forlubricating a refrigeration system.

A further object of the invention is to lubricate a refrigeration systemwithout injecting air or moisture into the refrigeration system.

Another object of the invention is to lubricate a refrigeration systemwhile the refrigeration system is in operation.

A still further object of this invention is to provide a system forlubricating a refrigeration system which utilizes primarily readilyavailable equipment, is economical and will have a long service life.

Other objects and advantages of the invention will be evident from thefollowing detailed description when read in conjunction with theaccompanying drawings which illustrate the invention.

In the drawings:

FIG. 1 is a diagrammatic view of a refrigeration system and my inventionapplied thereto.

FIG. 2 is a vertical sectional view through one form of lubricantcontainer utilized in the present invention.

FIG. 3 is a vertical sectional view through a modified form of lubricantcontainer assembly utilized in the present invention.

FIG. 4 is a diagrammatic view of a portion of a refrigeration system ofthe type shown in FIG. 1, showing use of the modified containerassembly.

Referring to the drawings in detail, and particularly FIG. 1, referencecharacter It] generally designates a typical refrigeration systemcomprising a compressor 12 and a motor 14 for the compressor constructedas an integrated unit, such as in a hermetically sealed unit. Thedischarge 16 of the compressor 12 is connected by a suitble conduit 18to a condenser 20. Refrigerant is condensed in the condenser 20 by thecooling action of air forced over the condenser by a motor driven fan22. The condensed refrigerant is conveyed through a capillary tube 24 toan evaporator 26. The refrigerant is vaporized in the evaporator 26,thus absorbing heat, and is returned to the suction 28 of the compressor12 through a suitable conductor 34).

A conventional service valve 32 is interposed in the tube 30. One port34 of the service valve 32 is connected to that portion of the tube 30leading to the evaporator 26, and a port 36 of the service valve isconnected to an extension 30a of the tube 30 leading to the suction 28of the compressor 12. The service valve 32 is also provided with what isnormally considered a service port 38 and an operating stem 40. In oneposition of the stem 40, the ports 34 and 36 are placed in communicationand the service port 38- is isolated for the normal operation of therefrigeration system 10. When the stem 40 is threaded a short distanceinto the service valve 32, the service port 38 is connected to the ports34 and 36, and when the stem 40 is threaded all the way into the servicevalve 32, the service port 38 is connected to the port 36, but the port34 is closed off.

The present invention contemplates a novel container assembly 42connected to the service port 38 of the service valve 32 by a tube orhose 44, and to a bottle 46 of refrigerant by means of a hose 48. Therefrigerant in the bottle 46 will be the same type of refrigerant usedin the refrigeration system 10 and may be, for example,dichlorodifiuoromethane, sold under the tradename of Freon. Therefrigerant in the bottle 46 will be at a pressure higher than thepressure of the refrigerant in the system 10 at the suction side 28 ofthe compressor 12. For example, the pressure of Freon-22 at the suction28 of the compressor 12 may be 78 p.s.i. with an outside temperature ofand the pressure of the refrigerant in the bottle 46 may be p.s.i. underthe same atmospheric conditions. It should also be noted here that asuitable hand-operated valve 50 is interposed in the hose 48 between thebottle 46 and the container 42 for controlling the flow of therefrigerant from the bottle 46.

The container assembly 42 is shown in detail in FIG. 2 and comprises anysuitably-shaped container 51 of sufiicient strength to withstand themaximum pressure to be applied thereto from the bottle 46. In theembodiment shown in FIG. 2, the container 51 is a cylindrical metal canhaving an externally threaded neck 52 at the upper end 54 thereof. Asuitable cap 56 is threaded for screwing onto and off of the neck 52 andis provided with a sight glass 58 in the top thereof. The sight glass 58may be any suitable transparent material sealed in a mating aperature 60in the cap 56 in order that the operator of the system can see into thecontainer 51, as will be more fully set forth below.

An inlet connector 62 extends through a mating aperture 64 in one wallof the cap 56 and is preferably turned downwardly at its inner end 66 toapproximately the lower end of the neck 52. The connector 62 is securedand sealed in the aperture 64 in any suitable manner, such as by welding68. The outer end 70 of the connector 62 is externally threaded forconnection with the hose 48 by suitable hose connector, not shown indetail.

An outlet connector 72 is secured in a mating aperture 74 in theopposite wall of the cap 56 in any suitable manner, such as by welding76. The outer end 78 of the connector 72 is also externally threaded forconnection with the hose 44. Finally, a supply of lubricant 80 isdeposited in the container 51, partially filling the container 51.

In use of the present invention, the inlet connector 62 of the containerassembly 42 is connected to the refrigerant bottle 46 by the hose 48,and one end of the hose 44 is connected to the discharge connector 72 ofthe container. The container assembly 42 is then held in an uprightposition as indicated by the dashed lines in FIG. 1 and the valve 50 ismomentarily opened. It will then be seen that refrigerant from thebottle 46 will pass through the hose 48 and into the upper portion ofthe container assembly 42 through the inlet connector 62. Thisrefrigerant will then pass out through the outlet connector 72 andthrough the hose 44. The refrigerant thus passed through the hose 48,the container assembly 42 and the hose 44 will clear the upper portionof the container assembly above the level of the lubricant 80, as wellas the hoses 48 and 44, of air and moisture which may be entrainedtherein. It will also be evident that these portions of the system willthen be filled with vapor ized refrigerant and such conditions will bemaintained at least momentarily.

As soon as the valve 50 is closed, the end 82 of the hose 44 isconnected to the service port 38 of the service valve 32, and thecontainer assembly 42 is inverted as shown in full lines in FIG. 1. Thestem 40 of the service valve 32 is operated to place the service port 38in communication with the ports 34 and 36, and the valve 50 is opened.The higher pressure refrigerant in the bottle 46 will then flow throughthe hose 48 into What is now the lower end of the container assembly 42and then upwardly through the lubricant to the space in the containerabove the lubricant. The refrigerant thus forces the lubricant 80through the outlet connector 72, hose 44, service valve 32 and hoseportion a into the suction 28 of the compressor 12. The operatorobserves the sight glass 58 during this operation and will thus be ableto tell when all of the lubricant 80 has been removed from the containerassembly 42. As soon as all of the lubricant 80 is forced into thecompressor 12, the stem of the service valve 32 is turned to theposition where the ports 34 and 36 are in communication but the serviceport 38 is isolated. As soon thereafter as possible, the valve is closedto close off the bottle 46 from the container assembly 42.

Upon completion of the above operation, the hoses 44 and 48 may bedisconnected from the service valve 32 and container assembly 42. Thecap 56 of the container assembly is then removed and a new supply oflubricant 80 placed in the container 51. The lubricant 80 will normallybe a high grade mineral lubricant. When the desired quantity oflubricant is deposited in the container 51, the cap 56 is threaded backonto the neck 58 and suitable protector caps (not shown) are thenpreferably placed over the outer ends 70 and 78 of the connectors 62 and72 to prevent the entrance of dirt into the container assembly 42. Thelubrication system will then be ready for another service job at adifferent location. It will be readily understood, however, that the cap56 may be permanently secured on the container 51 and the entirecontainer assembly disposed of at the completion of a service job.

It may also be noted at this point that the amount of lubricant in thecontainer 51 may be easily designed to be the normal amount of lubricantadded to a refrigeration system of the type being serviced, in whichevent the entire amount of lubricant 80 is forced into the refrigerationsystem in the manner set forth above. On the other hand, the container51 may be large and more lubricant 80 contained therein than is normallyplaced in a refrigeration system 10. In this latter event, the operatorwould need to time the injection of lubricant into the refrigerationsystem or provide a transparent graduated scale in the side wall of thecontainer 51.

An alternate embodiment of the invention is illustrated in FIGS. 3 and4. This embodiment of the invention utilizes a modified containerassembly which includes a container portion 102 and a valve portion 104.The container portion 102 is a sealed container 106 preferably in theform of a metal can of the type presently used for storing small amountsof refrigerant under pressure. The container 106 includes an externallythreaded neck 108 on the upper end thereof forming a connector for thevalve portion 104, as will be described. The upper end of the connector108 is closed by a sealing material 110, in the conventional manner,which may be pierced by a piercing valve. The container 106 alsoincludes an annular projection 112 positioned concentrically around theconnector 108 in the usual fashion. The lubricant supply 80 isvacuum-packed in the container 106 and only partially fills thecontainer 106. By being vacuumpacked, the container 106 is less likelyto have moisture condensed therein when the container is stored undervarying climatic conditions and, of course, the container then alsocontains a very nominal amount of air.

The valve portion 104 preferably comprises what is known as a doubleport, piercing-type valve, such as is manufactured by Watsco, Inc. ofHialeah, Florida, under the designation Twin Port, Can Tap Valve. Thevalve 104 includes a body portion 114 having externally threadedconnectors 116 and 118 on the opposite sides thereof forming ports 120and 122 for the valve. The lower end 124 of the valve is internallythreaded for connection with the externally threaded connector 108 ofthe contanier 106. The lower end of the valve 104 also includes asealing ring 126 positioned to seal the upper end 110 of the connector108 when the upper end 110 is pierced by the stern 128 of the valve, aswill be more fully set forth below.

The valve stem 128 is threaded into the bore or valve chamber 130 of thevalve and is normally retained in place in the valve by a cap portion132 threaded around the upper end of the valve body 114. A suitablehandle 134 is secured to the upper end of the valve stem 128 for turningthe valve stem and thus raising and lowering the valve stem in the valvebody, as will be described. The valve 104 also includes a locking ring136 threadedly secured around the valve body 114 below the connectors116 and 118 for engagement with the annular projection 112 on thecontainer 106 in the usual manner. It should also be noted here that thevalve 104 is shown as being almost completely formed of a plasticmaterial, although it will be understood that the valve may be formed ofany desired material which will withstand the pressure to beencountered.

In use of the modified container assembly 100, the lubricant 80 is firstvacuum-packed in the container 106 in the manner described to removesubstantially all of the air from the container and minimize thepossibility of moisture condensing in the container duringtransportation and storage. When it is desired to lubricate a refrigeration system, the valve 104 is threaded onto the connector 108 ofthe container 106, and the locking ring 136 is threaded down intoengagement with the projection 112 to firmly secure the valve 104 on thecontainer 106. It will, of course, be understood that the valve stem 128is retracted into the body 114 while the valve is being secured on thecontainer.

The container assembly 100 is then connected to the refrigeration systemas partially shown in FIG, 4. It will there be noted that the hose 48leading from the refrigerant supply is connected to the connector 118 ofthe valve 104, and one end of the hose 44 is secured to the oppositeconnector 116 of the valve. During this initial portion of theoperation, the opposite end 82 of the hose 44 is not connected to theservice valve 32.

While the container assembly 100 is retained in an upright position asillustrated by the dashed lines in FIG. 4, the valve 50 is momentarilyopened to pass a charge of refrigerant through the hose 48; the part 122of the valve 104; the valve chamber 130; the opposite port 120 of thevalve 104, and through the hose 44 to remove air and moisture from thehoses 47 and 44 and the valve 104. During the operation just described,the valve stem 128 may either be in a retracted position removed fromthe end 110 of the container connector 108, or the pointed end of thestem 128 may be in a piercing position extending partially through theend 110 of the connector 108. In either event, the valve chamber 130 isclosed from the interior of the container 106. As long as the lower,pointed end of the valve stem 128 is in a position extending into theend 110 of the connector 108, the sealing ring 126 effectively preventscommunication between the valve chamber 130 and the container 106.

The container assembly 100 is then inverted to the full line positionshown in FIG. 4, and the end 82 of the hose 44 is connected to theservice port 38 of the service valve 32, while the service valve 32 ismaintained in a position to close the service port 38 from the ports 34and 36. The piercing valve 104 is then operated by turning the handle134 to pierce the seal 110 in the connector 108 of the container 106 andthen to withdraw the pointed end of the stem 128 into the valve chamberto provide communication between the valve chamber 130 and the interiorof the container 106. When such communication is established, the valve50 is opened for a short period of time to direct high pressurerefrigerant through the hose 48, the port 122 of the valve 104, thevalve chamber 130 and into the container 106 to fill the space in thecontainer which will then be above the level of the lubricant 80 in theinverted container. As soon as a supply of the high pressure refrigerantis thus introduced into what is then the upper end of the container 106,the valve 50 is closed and the service valve 32 is operated to providecommunication between the service port 38 and the port 36 communicatingwith the suction of the compressor 12 through the hose portion 30a. Assoon as this lastdescribed communication is established, the highpressure refrigerant in the top of the container 106 forces thelubricant 80 through the upper end 110 of the container connector 108;the valve chamber 130; the port 120; the hose 44, the service valve 32,and the hose portion 301; into the suction 28 of the compressor 12. Thelubricant 80 will thus be introduced into the refrigeration system inonly a matter of minutes; whereupon the service valve 32 is againoperated to close off the service port 38 from either of the ports 34 or36 in the manner described above.

In the embodiment of the invention illustrated in FIGS. 3 and 4, thepiercing valve 104 will, of course, be used in a large number ofsuccessive lubricating jobs. Since the lubricant in this embodiment isvacuum-packed in the container 106, the container 106 will normally bedisposed of after being used in a lubricating operation and a newcontainer 106 will be required for the next lubricating job. However,the container 106 could be saved and returned to the supplier of thevacuum-packed lubricating oil for reuse 'by rescaling the upper end 110of the connector 108. Insofar as the service man is concerned, however,a new container 106 containing the vacuum-packed lubricant 80 will beused in each lubricating job, assuming the container 106 is sized toretain the desired amount of lubricant 80 for the particularrefrigeration system being lubricated. In the event the container 106being used contains a larger or excessive amount of lubricant 80, thevalve 104 may be moved to the position illustrated in FIG. 3 when theservice man determines the desired amount of lubricant 80 has beenejected into the refrigeration system. In this position of the valve104, as previously noted, the seal 126 effectively seals the valvechamber 130 from the interior of the container 106. Thus, the container106 could then be used in a subsequent lubricating job by following thesame operating procedure outlined above.

From the foregoing it will be apparent that by use of the presentinvention a refrigeration system may be lubricated while therefrigeration system is in operation. The service valve may be easilymanipulated to connect all of the ports therein while lubricant is beingforced into the compressor and maintain the normal flow of refrigerantthrough the refrigeration system. Since the refrigeration system doesnot need to be pumped down, the minimum time will be required tolubricate the refrigeration system. It will also be apparent that in useof the present invention no air, moisture or dirt will be introducedinto the refrigeration system.

Changes may be made in the combination and arrangement of parts orelements, as well as in the steps and procedures, heretofore set forthin the specification and shown in the drawings without departing fromthe spirit and scope of the invention as defined in the followingclaims.

What is claimed is:

1. A method of lubricating a refrigeration system having a compressorcomprising:

partially fill-ing a container with lubricant for the refrigerationsystem;

forcing refrigerant under pressure through the container above thelubricant therein to remove substantially all of the air from thecontainer; inverting the container; connecting the then lowermost end ofthe inverted container to the suction side of the compressor; and

applying refrigerant to the container under a pressure greater than thesuction pressure of the compressor to force lubricant from the containerinto the compressor suction until the desired amount of lubricant hasbeen supplied to the refrigeration system.

2. A method of lubricating a refrigeration system having 'a compressor,comp-rising:

partially filling a container with lubricant for the refrigerationsystem;

connecting a hose to the upper end of the container;

forcing refrigerant under pressure through the container above thelubricant therein to remove substantially all of the air from thecontainer and said hose;

inverting the container;

connecting said hose to the suction side of the corn pressor; and

applying refrigerant to the container under a pressure greater than thesuction pressure of the compressor to force lubricant from the containerthrough said hose into the compressor suction until the desired amountof lubricant has been supplied to the refrigeration system.

3. A method of lubricating a refrigeration system having a service valveinterposed in the connect-ion of the evaporator to the compressor of thesystem, and wherein the service valve has a service port, comprising:

connecting a bottle of refrigerant gas under a pressure greater than thepressure at the suction side of the compressor to the top of a containerpartially filled with lubricant;

connecting one .end of a hose to the top of said container;

discharging a quantity of refrigerant from the bottle through the top ofsaid container and hose to remove air therefrom;

connecting the opposite end of said hose to the service port of theservice valve;

inverting said container;

opening the service valve to communicate the service port with thecompressor;

passing refrigerant from the bottle through said inverted container andhose into the refrigeration system until the desired amount of lubricanthas been forced from said container into the refrigeration system; thenoperating the service valve to isolate the service port from therefrigeration system.

4. A method of lubricating an operating refrigeration system having aservice valve interposed in the connection of the evaporator to thecompressor of the system, and wherein the service valve has a serviceport, comprising:

connecting a bottle of refrigerant gas under a pressure greater than thepressure at the suction side of the compressor to the top of a containerpartially filled with lubricant;

connecting one end of a hose to the top of said eontainer;

discharging a quantity of refrigerant from the bottle through the top ofsaid container and hose to remove air therefrom;

connecting the opposite end of said hose to the service port of theservice valve;

inverting said container;

opening the service valve to communicate the service port with thecompressor and the evaporator of the refrigeration system;

passing refrigerant from the bottle through said container and hose intothe refrigeration system until the desired amount of lubricant has beenforced from said container into the refrigeration system; then operatingthe service valve to isolate the service port from the refrigerationsystem.

5. A system for lubricating a refrigeration system having a compressorwhile the refrigeration system is in operation, comprising:

an invertible container having an upper end and a lower end and havinginlet and outlet connectors on the upper end thereof;

a supply of refrigeration lubricant partially filling the container;

a hose for connecting the outlet of the container to the suction side ofthe compressor; and

means for forcing refrigerant under pressure through the upper portionof the container and said hose when the container is in an uprightposition to remove air from the container and hose, and for forcing thelubricant from the container through the hose into the suction of thecompressor with refrigerant when the container is in an invertedposition.

6. A system as defined in claim wherein said container has a cap securedon the upper end thereof, and said inlet and outlet connectors aresecured in sadi cap.

7. A system as defined in claim 6 characterized further to include asight glass in said cap to indicate the removal of lubricant from thecontainer when the container is inverted.

8. Asystem as defined in claim 6 wherein said cap is threadedlyconnected to said container to facilitate replenishing the lubricant inthe container.

9. A method of lubricating a refrigeration system having a compressor,comprising:

partially filling a container with lubricant for the refrigerationsystem; connecting one end of a hose to the container; passingrefrigerant through the hose to clean the hose of air and moisture;inverting the container; filling the space above the lubricant in theinverted container with a supply of refrigerant under a pressure greaterthan the suction pressure of the compressor; and connecting the oppositeend of the hose to the suction of the compressor, whereby saidrefrigerant under pressure forces the lubricant through the hose intothe compressor while the compressor is in operation. 10. A method oflubricating a refrigeration system having a compressor and a servicevalve connected to the suction of the compressor, and wherein theservice valve has a service .port, comprising:

vacuum packing lubricant for the refrigeration system in a sealedcontainer wherein the container is only partially filled with lubricant;

securing a double ported, piercing valve to the container above thelubricant in the container;

connecting one end of a hose to one of the ports of the piercing valve;

passing refrigerant through the opposite port of the piercing valve, thepiercing valve above the container and on through the hose to clearthese members of air and moisture;

connecting the opposite end of the hose to the service port of theservice valve While the service port of the service valve is closed;

piercing the container with the piercing valve above the level oflubricant in the container and communicating the interior of thecontainer with the interior of the piercing valve while communicating asupply of refrigerant under a pressure greater than the suction pressureof the compressor to the interior of piercing valve through saidopposite port;

closing said opposite port of the piercing valve;

inverting the container, whereby the supply of refrigerant formerly inthe top of the container will pass through the lubricant in thecontainer and again be above the lubricant in the container; and

opening the service port of the service valve to the compressor suction,whereby the refrigerant in the container forces the lubricant from thecontainer through the piercing valve hose and service valve into thecompressor suction.

11."A system for lubricating a refrigeration system having a compressorwhile the refrigeration system is in operation, comprising:

an invertible container assembly having an upper end and a lower end andhaving inlet and outlet connectors on the upper end thereof;

a supply of refrigeration lubricant partially filling the containerassembly;

a hose for connecting the outlet of the container assembly to thesuction side of the compressor; and

means for forcing refrigerant under pressure through the upper portionof the container assembly and said hose when the container assembly isin an upright position to remove air from the upper portion of thecontainer assembly'and the hose and for filling the space in thecontainer above the lubricant when the container is in an invertedposition for forcing the lubricant from the container through the hoseinto the suction side of the compressor.

12. A system for lubricating a refrigeration system having a compressorwhile the refrigeration system is in operation, comprising:

9 a sealed container having refrigerant lubricant vacuumpacked thereinpartially filling the container, said container having a threadedconnector thereon;

a double ported piercing valve sized to be connected References Cited bythe Examiner UNITED STATES PATENTS Peo 62-77 Wood 6277 Shoemaker 62149Haas 62-192 X Ehrens 6 2-292 Alexander 6277 ROBERT A. OLEARY, PrimaryExaminer.

l5 LLOYD L. KING, Examiner.

1. A METHOD OF LUBRICATING A REFRIGERATION SYSTEM HAVING A COMPRESSORCOMPRISING: PARTIALLY FILLING A CONTAINER WITH LUBRICANT FOR THEREFRIGERATION SYSTEM; FORCING REFRIGERANT UNDER PRESSURE THROUGH THECONTAINER ABOVE THE LUBRICANT THEREIN THE REMOVE SUBSTANTIALLY ALL OFTHE AIR FROM THE CONTAINER; INVERTING THE CONTAINER; CONNECTING THE THENLOWERMOST END OF THE INVERTED CONTAINER TO THE SUCTION SIDE OF THECOMPRESSOR; AND APPLYING REFRIGERANT TO THE CONTAINER UNDER A PRESSUREGREATER THAN THE SUCTION PRESSURE OF THE CONTAINER TO FORCE LUBRICANTFROM THE CONTAINER INTO THE COMPRESSOR SUCTION UNTIL THE DESIRED AMOUNTOF LUBRICANT HAS BEEN SUPPLIED TO THE REFRIGERATION SYSTEM.